browser_adapter.js:77 EXCEPTION: Error during instantiation of Token Promise<ComponentRef>!.BrowserDomAdapter.logError
browser_adapter.js:77 ORIGINAL EXCEPTION: Expected 'styles' to be an array of strings.

Unfortunately, that location is not readily known. Angular apps can be loaded in many ways: from individual files, from SystemJS bundles, or from CommonJS bundles, to name a few. With this diversity of load strategies, it's not easy to tell at runtime where these files actually reside.

The only location Angular can be sure of is the URL of the index.html home page. So by default it resolves template and style paths relative to the URL of index.html. That's why we previously wrote our CSS file URLs with an app/ base path prefix.